Mastodon bones unearthed at Michigan construction site

BYRON TOWNSHIP, MI - Experts from the University of Michigan have been called in to investigate the discovery of prehistoric mastodon bones at a work site south of Grand Rapids.

The owner of the property, a housing development located west of Byron Center Avenue, could only guess at the origin of the strange bones found in the ground Thursday, Aug. 31.

"We didn't know until late yesterday what we had," said Joe Siereveld, an owner and partner in Eagle Creek Homes and the Railview Ridge development near Byron Center.

Siereveld said workers were surprised to find "some interesting items" Thursday while doing road excavation at the site. It wasn't until Tuesday, Sept. 5, that a University of Michigan researcher delivered the news that what they had were the remains of a 10,000-some-year-old mastodon skeleton.

"We ended up finding what the University of Michigan has told us were mastodon bones," Siereveld said. "They were deep; really, really deep."

As of now, he said, the company is in possession of four pieces of bone that researchers believe belonged to a male American mastodon that lived to the age of 20-30.

A Facebook post on Sept. 1 shared photographs of "huge bones" found on a property near Byron Center, suggesting they might have once belonged to an enormous prehistoric mammal.

Eagle Creek Homes, the developer behind the Railview Ridge housing project, reached out to University of Michigan Museum of Paleontology Director Dan Fisher. Fisher has 40 years of experience investigating claims of prehistoric remains found in the region.

"It's not that I'm the only one that can or will work on them, but I'm probably the main one who does," Fisher said.

Fisher confirmed he was contacted by the property owner in Byron Center to investigate the legitimacy of the potential find. One of his assistants was in the area and stopped by the site, he said.

Eagle Creek Homes is currenlty in possession of five large pieces of the mastodon skeleton and a few smaller pieces. At least two of the pieces appear to have come from the animal's head.

In cases where a discovery is confirmed as legitimate, Fisher said, he offers his services as an expert and, if asked, will sit down with property owners and present them with their options. If an owner offers to donate a specimen to the university, he said, the museum might then become involved in an excavation at the site.

"It's their call whether they're going to donate it or not," Fisher said. "The usual pattern is I ask them to think about it, and they let us know when they've decided what they want to do with the material."

Siereveld said the company is in discussions with the University of Michigan about potentially donating the bones and working with the school at the site.

"We're in talks right now of having them handle the bones that we currently got," he said. "Right now trying to work on the details."

Some property owners prefer to hold onto specimens or attempt to sell them, Fisher said. In other cases, he said, potential discoveries are ultimately revealed to be something other than an addition to the prehistoric fossil record.

"There are a few things that turn out to be, shall we say, false alarms," Fisher said. "Cow bones, horse bones, things like that."

But legitimate discoveries of prehistoric animals like mastodons or mammoths are also not entirely uncommon in the area, he said. Fisher estimated two or three such discoveries in Michigan each year.

Fisher said finds with a large section of the animal's remains still intact are particularly rare. In most cases, he said, only a small portion of the bones remain.

But he still gets excited at the prospect of any legitimate find, saying they can shed light on the animals themselves as well as their interaction with early humans present in North America.

"There is very interesting scientific work to be done on them," Fisher said.

Most remains of mastodons and mammoths found in Michigan, Fisher said, are somewhere in the range of 11,000 to 15,000 years old.

"That was at a time that humans had found their way to North America," Fisher said. "These were some of the animals that they were sometimes lucky enough to bring down or otherwise get access to. So people butchered them, ate them and stored their meat."

As glaciers moved through Michigan several thousand years ago, they created lakes, ponds and swamps that became surrounded by vegetation attractive to the American mastodon and Jefferson woolly mammoth. Fossils of both are prevalent in the southern two-thirds of the state.

The age of the bones means they are often very fragile, and can sometimes disintegrate when exposed from the sediment that has been preserving them all that time.